Allogeneic Bone-Marrow Mesenchymal Stem Cell with Moldable Cryogel for Craniofacial Bone Regeneration

Allogeneic bone-marrow mesenchymal stem cells (BMSCs) can promote bone regeneration and substitute for autologous BMSCs if autologous sources are unavailable, but the efficacy of bone regeneration by allogeneic BMSCs is still inconsistent. A Lewis rat cranium defect model was used to investigate the efficacy of bone regeneration between autologous and allogeneic BMSCs in gelatin-nanohydroxyapatite cryogel scaffolds. BMSCs from Wistar rats served as the allogeneic cell lineage. The full-thickness cranium defects were treated by either blank control, cryogel only, allogeneic BMSC-seeded cryogel, or autologous BMSC-seeded cryogel (n = 5). Bone regeneration was monitored by micro-computed tomography and examined histologically at week 12. In addition, we assessed the immune responses in vitro by mixed lymphocyte reaction (MLR) assay and CD4+ immunochemistry staining ex vivo. The MLR showed that allogeneic BSMCs elicited a weak immune response on day 14 that progressively attenuated by day 28. In vivo, the bone regeneration in allogeneic BMSCs was inferior at week 4, but progressively matched the autologous BMSCs by week 12. Our results suggest that allogeneic BMSCs can serve as an alternative source for bone regeneration.

Allogeneic bone marrow transplantation possibly induces a localized type of porokeratosis

A 15-year-old girl underwent allogenic bone marrow transplantation for neuroblastoma. A few years later, she noticed a round lesion on her left buttock. Since the lesion had been asymptomatic and never grown, more than 20 years had passed before she saw a local doctor to consult about it. Although the lesion was suspected to be tinea corporis, no fungi were found on microscopic examination. Subsequently, administered topical corticosteroids were not effective. She was referred to our hospital for further evaluation, and a skin biopsy confirmed the diagnosis of porokeratosis. There was a possibility that chemotherapy, total body radiation, or immunosuppressive therapy associated with allogeneic bone marrow transplantation was involved in the development of porokeratosis. Numerous cases of acquired porokeratosis in immunocompromised status have been observed; as for those after allogenic bone marrow transplantation, 12 cases have been reported in the English literature, 4 of which had only one or a few lesions on a limited area of body surface. Our case was relatively uncommon in that the lesion was solitary and comparatively large. In a localized type of porokeratosis, it was suggested that a malignant skin tumor developed earlier than in other types. Careful follow-up for malignant transformation is especially required.